When a serum test overrides the clinical assessment

The clinical features of narcolepsy-cataplexy are substantially different from anti-NMDA receptor (NMDAR) encephalitis. We report a patient whose diagnosis was established only after traditional clinical assessments prevailed over a presumably abnormal serum test result. Acknowledgment: The authors thank the patient and her family, who provided clinical information; Dr. Myrna R. Rosenfeld (Neuroimmunology Program, Institut d'Investigació Biomèdica August Pi i Sunyer [IDIBAPS], Hospital Clínic, University of Barcelona, Spain) for critical review of the manuscript; and Dr. Carles Gaig (Multidisciplinary Sleep Disorders Unit and Service of Neurology, Hospital Clínic, University of Barcelona, Spain) and Dr. Manuel Morales-Ruiz (Biochemistry and Molecular Genetics, Institut d'Investigació Biomèdica August Pi i Sunyer [IDIBAPS], Hospital Clínic, University of Barcelona, Spain) for CSF hypocretin-1 testing.